The present invention relates to a an improved system for drilling holes in ceilings.
By way of background, in my copending application Ser. No. 107,650, filed Oct. 13, 1987, a system is shown for drilling holes in ceilings by use of a hammer drill mounted on an elongated rod which bears on the floor. In this system a pneumatic cylinder supplies the force for supporting the hammer drill and also feeding it into the ceiling with a constant force. This structure was developed so that the drill operator did not have to support the drill which weighed approximately fifteen pounds. However, it has been found that the drill could be jerked out of position if it was subjected to shock loading when the drill bit struck embedded reinforcing rods in concrete ceilings.